A worker produced a batch of parts. On the first day, he produced part of the parts, and the ratio of the number of finished parts to the number of unfinished parts was 3:4. On the second day, he produced another 52 parts. At this time, the number of finished parts was 4 times of the number of unfinished parts. How many parts were produced on the first day?

A worker produced a batch of parts. On the first day, he produced part of the parts, and the ratio of the number of finished parts to the number of unfinished parts was 3:4. On the second day, he produced another 52 parts. At this time, the number of finished parts was 4 times of the number of unfinished parts. How many parts were produced on the first day?

Suppose the total production is x, then the first day is 3x / 7 of the total production, and the first two days is 4x / 5 of the total production
So the equation is 3x / 7 + 52 = 4x / 5, and the solution is (28-15) x / 35 = 52, x = 140
On the first day, 140 * 3 / 7 = 60 were produced